Pete Wentz 'On Call Permanently' for Baby's Birth

"She is very pregnant," the Fall Out Boy bassist told Ryan Seacrest on Thursday. "I am on call permanently right now. She's at the very end, and it could happen at any point."

Wentz, who will attempt to break a world record for most radio interviews in 24 hours with band-mate Patrick Stump on Friday, adds that Simpson-Wentz, 24, is "excited" to become a mom.

"She [feels] hot all the time," says Wentz, 29, joking that the couple's thermostat is set to 34 degrees. "I think she wants to just be not pregnant anymore ... It's a struggle to go up and down the stairs. Going out in public is insane."

Another milestone the pair is looking forward to is naming their little one – but not until after the birth.

"I want to meet [the baby] first," says Wentz, adding that he has a formula in place for when the time comes. "My friend said it – you've gotta have a baby with a name that could be a rock star or a senator, so he'll get work either way."